V2

I have made several improvements to the game, fixing some bugs and overhauling mechanics. 

- Added wall kicks: if there is room, rotating a piece can "push" off of the wall

- Added hard drop: Shift + Down drops piece immediately

- Added directional rotate: Shift + Up rotates clockwise instead of counter clockwise

- Added directional cycle: Shift + Tab will cycle through pieces in the opposite direction, so you don't have to cycle through again for a missed piece

- Added an avoidable game over failsafe, which prevents ending a turn if you have a piece in the starting zone with moves left

- Overhauled move system. Moves are now shared, and can be earned by clearing lines. Getting a tetris (four lines at once) gives you temporary unlimited moves until you end your turn.